Drying of road-making aggregates and other broken or granular materials



Apnl 22, 1930.. J. F. WAKE 1,755,377

DRYING OF ROAD MAKING AGGREGATES AND OTHER BROKEN 0R GRANULAR MATERIALS Filed Sept. 21, 1925 2 Sheets-Sheet 1 April 22, 1930. J. F. WAKE 1,755,377

DRYING OF ROAD MAKING AGGREGATES AND OTHER BROKEN OR GRANULAR MATERIALS Filed Sept. 21, 1925 2 Sheets-Sheet 2 FLQ. 5. Fly 4 .36

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Patented Apr. 22, 1930 UNITED JOHN FREDERICK WAKE, F DABLINGTON, ENGLAND DRYING OF ROAD-MAKING AGGREGATES AND OTHER BROKEN OR GRANULAR MATERIALS 7 Application filed September 21, 1925,.Seria1 No. 57,667, and in Great Britain September 2351924.

This invention relates to the drying of broken or granular materials in bulk, such as road-making aggregates, by a fluid drying medium or agent.-

5 The invenion is directed to that type of drying which is effected on, what is or may be termed, the counter-current principle, that is to say, of the kind wherein the material is, in the process of drying, compelled to travel in a direction opposite to that followed by the drying medium or agent.

The object of the invention is to obtain highly efficient drying simply and inexpensively; and to provide an apparatus or dryer free of moving mechanism apart from the customary adjuncts necessary to compose a complete plant, such as, for instance, the elevators which feed and discharge the material, and the fans for use in connection with the funaces to supply heated air to constitute the drying medium or agent.

To this end, I constrain the material to flow or move gravitationally and continuously in an independent stream or column or streams as or columns while subject to the drying medium or agent constrained to flow and circulate in the opposite direction, the streamor column or each of the streams or columns being of a symmetrical contour from end to end.

The stream-flow or columnar-movement of the mass of material is successively concentrated, disrupted and collapsed, or contract ed and expanded, thereby producing a pulsation of the whole streamor column-mass promoting the continual exposure of fresh surfaces of the material to the drying medium or agent.

Plant or apparatus for effecting the drying as explained comprises a casing whoreinto the material is fed; a plurality of open-ended tubes or pipes positioned within the casing through which the material passes under gravity, and provided with spaced openings throughout their length establishing communication with the casing; means for supplying a drying medium or agent to the casing whence it passes into thetubes or pipes; means for withdrawing the spent drying medium or agent and moisture from the casing 5e and the tubes or pipes; means for charging the material to be dried into thecasing and tubes or pipes and means for discharging the dried material therefrom.

The tubes or pipes are each composed of intercommunicating parts adapted to admit or compel the alternate contraction or expansion, or concentration, disruption and collapsion, of the material passing therethrough as a stream or column as it is fed at one end of the tube or pipe and discharged at the other end while the drying medium or agent is introduced into the tube or pipe at the latter end and discharged at the opposite end.

I will now describe, by way of example, one way of, or apparatus for, carrying my invention into practice particularly applicable for drying broken stone for making tarred macadam for roads which I have illustrated more or less diagrammatically in the accompanying drawings whereto I willrefer as occasion requires, premising that of the several figures:

Fig. 1 is a central vertical sectional elevation of the apparatus constructed in accordance with the invention; and

Fig. 2 is a horizontal section thereof on the line XX; while Figs. 3, 4 and 5 are elevations of various modifications of the intercommunicating members, represented in'the last two figures, composing a tube or pipe.

The same numerals of reference are adopted throughout to designate the same or corresponding parts.

According to this example, I construct a cylinder to constitute a casing 10 which I set vertically upon an appropriate support or foundation 11. Within, and transversely of, the casing 10 I fix a plurality of plates 1414 in spaced relation constituting partitions forming a series of compartments. 15-15 within the casing 10, communication between these various compartments being suitably eifected. These plates or partitions 14.14, further, function to carry the components 'of a pluralitysix, for instance,of cylindrical sectionally-constructed vertically-arranged tubes or pipes 12-12 for the passage of the material to be dried, which is fed into the upper ends of the tubes or pipes from a we common supply chamber or hopper 23, and is discharged at the lower end into a common delivery chute 29 provided with an out-let 33, the flow of the material throughout being accomplished wholly by gravity.

Accordingly, each partition plate 14 has six equidistantholes near its periphery for the components or sections 8484 of the tubes or pipes 12-12 for which it acts as a tube-plate, while the top plate 14 and'the bottom-plate '14, are, in addition, provided with a central hole 35, the hole in the top plate 14 being for the discharge of the spent dryingmedium or agent and the products of the drying, and the hole 35 in the other plate 14 being for the inlet of thedrying medium or agent.

Each tube or pipe component or section '34 consists of a funnel-shaped member or tube, that is to say, it comprises a cone-shaped portion 36 merging into, and terminating in, a cylindrical portion??? of reduced diameter, the over-all length of the member 34 approximating the distance between two adjacent partition plates 14, 14, and the lengths of the conicaland cylindrical portions 36 and 37 being substantially the same. The upper end of the conical portion 36 of each member 34 is secured to the partition plate 14, while the complementary cylindrical or depending portion 37 depends with its end almostto (see Figure 1) or slightly projecting into the conical end 36 or the next subjacent member 34 (see Figure 3), with the exception of the lowermost which communicates with the delivery chute 29. The cylindrical or depending portion 37 of each member 34 isperipherally gapped, thegaps 3838 taking the form of spaced slots extendingfrom the extreme end for a distance towards the conical portion 36, and being of such dimensions as to permit of thepassage 'ot'the-material. Thus these gaps or slots 38- 38 constitute both outlets for the discharge of the material and inlets tor the supply of the drying medium or agent. Therefore, the assemblage of members34- 34 composes a complete tube or pipe 12 constraining'the material, as well as the drying medium or agent, to follow "a sinuous and interrupted course in passing through it. p

The feed or supply chamber 23 for the ma-- terial is formed as a continuation of the upper end of the casing 10, and it consists of a truncated-cone part whose base is constituted by the" uppermost partition plate 14, oi a reverse conical part'whereint'othe material is delivered through the agency of a shoot and an elevator.

The delivery chute 29 is likewise constituted as a continuation of the bottom end ofthe casing 10, and it, also, consists of an inclined wall part 28, a vertical wall part 30 and anupper wall formed by a plate 39 secured to the casing 10. The plate 39 is a counterpart of the lowermost partition plate 14 of the casing 10, and it is at a distance therefrom equal to the spacing of the partition plates 14-44, consequently the lowermost components, sections or members 8434 of the various tubes or pipes 1212 project closely to, or slightly into, the corresponding holes in the plate, while, too, acompartment 40 obtains whereinto the drying medium or agent is initially and directly introduced.

The outlet 44 through the plate 39, which communicates with a subjaccnt chute 29, is controlled by means comprising a disc 41 revolublyifitted thereover so as to'also constitute a part 01" the upper wall of the chute 29. The disc-41 is provided with .aplurality of peripheral openings 42 42, less innumber than ithat of'the sectional tubes or pipes 1212three, for instance. The disc .41 is mounted on ashaft 43 constituted, in theex ample, supported centrally of the chute '29 in :any suitable manner, and a worm shaft 45 and a worm gear 46 are combined in aappropriate fashionifor continuously or periodically rotating the disc 41.

A pipe 19 is-secured to the uppplate 14 about'the central hole '3 constitute an on tlet for: the spen t dium or agent and the products 0 inc and it'may be design-ed to e-per or chimney, or it ay bc c with suction orr itherllclice for enccti g a jpositive discharge. This outlet pipe projects through the feed or supply-chamber 23, and about its junction with h-e arti tion plate 14 a s ruc'ture '27 of tin: mo formation is po"tion for." the pu fleeting the material towards, or it, to the uppermost fur tions 36-36 of the components, members '01 the varic 12 12, thereby promoting equa teed.

The clryiiigniedinnior agent adopted is hot air supplied from or by a 11g appropriate source such as a furnace and, as alreadyexplained i" is introduced o the lowermost compai i 10,'th'a't isthe 'extr r ately above the deuvery chine Q9. ing 10, in proximity to this compart is surrounded bya bricl; line 20 co with the furnace or other source, 2rd con munication between the tn is e: -abl a plurality of portsZfZ-QZ provided walls of the casing 10 and ot the flue sequentl ,the hot air enters the com in. 40 whence some of it passes through e or slots 3888 of the comp members 34-34 of the va 1212 therein into the ne above, while some of it p;

n can ,"ilV or the central hole 35 in the partition-plate 14. Thus the hot alr passes'fromthe second compartment to the superimposed compartments 15-15 in turn by way of the pipe components, sections or members 3 l3 l, eventually entering the outlet pipe 19 for discharge as a spent medium or agent along with the products arising from the drying. I

If desired, thehot air may, also, be directly introduced into, and in the spent condition, along with the drying products, be withdrawn from, one or more of the superimposed compartments 1515, which may be the same or not, that is to say, the hot air may be supplied to a compartment 15 other than that from which it may be withdrawn. 7 This may be accomplished by extending a part 47 or parts of the main flue up the casing 10 and providing interconnecting ports t848 at the required places, and by furnishing a spentair outlet pipe49 or pipes having a branch or branches 5O connecting with the designed compartment 15 or compartments 1515, by way of suitable ports 51 51, the branch outlet pipe 49 or pipes being independent of, or allied with, and of the same operative character as, the main outlet pipe 19. The flue extension 47 or extensions and the outlet pipe 4.9 or pipes may be situated without the casing 10. The various ports 4848 and 5151 for the active and spent medium or agent are controlled by valves as indicated at 5252, or otherwise, adapted to be actuated to effect any desired system or sequence of operation.

It will now be obvious that, when the plant is in full work, the various sectional tubes or pipes 1212 are fully charged with mat-crial, and likewise the delivery chute 29 and the feed or supply chamber 23, and that the material, as it approaches the bottom of the tubes or pipes 12-12, becomes more dry and is subjected to the drying medium or agent when hottest. It will, further, be seen that the material, as it enters each cylindrical por tion 37 of a pipe component, section or member 35%, concentrates or contracts to form a column which disrupts or expands through the gaps or slots 38-38 therein, and, when it reaches the funnel portion 36 of the next section 34:, it further disrupts or bulges or expands and collapses, and then is reassembled or concentrated or contracted as a column again in and by the cylindrical portion 37 of that funnel 36, when the same actions are successively or alternately repeated until the material falls or discharges into the delivery chute 29, while simultaneously the hot air is split up and circulated through and around the concentrated, disrupted and collapsed material. Thus the material, when it enters the delivery chute 29, by the rotation of the disc 41 is thoroughly and uniformly dry because the expanding, disrupting collapsing actions function as a means of agitating and changing the position of the pieces composing the bulk material, whereby fresh surfaces are continually being exposed to the hot air, with the consequential advan tageou's drying effect.

It will be obvious that the formation of the components or sections 34-34 of the tubes or pipes 1212 may be variously modified whilst retaining the pulsating action of the material in the course of its stream-flow or columnar movement. Three examples of this are illustrated in Figs; 3, 4 and 5 to which I will refer in turn.

Fig. 3 represents each component or section fashioned, as a continuous conical tubular member 34, the basal'end 36 of one cone being assembled relatively to the apexal end 37 a of the adjacent cone 34 as shown, and in much the same Way as the parts 36 and 37 already described with reference to, and as illustrated in, Fig. 1. 6

According to Fig. 4, the component or-section 343 is of compound structure whose constituents resemble the constituents 36 and 37 of the Fig. 1 construction, inasmuch as it comprises a conical tubular member 36 and a reversely-conical deflector 37 the two be ing suitably connected together. Here, again, the components or sections 34 34" are assembled so that the relation of the parts 37 37 b with reference to the parts 36 36 is as explained with regard to the original construction.

The construction illustrated in Fig. 5 is substantially the same as that just described, the difference being that the constituent or element 36 is fashioned as a basin with an opening in its bottom wherewith the apex of the constituent or deflector 37 is associated.

In each of these three modifications, the parts 36, 36 36 and 36 are supported by the partitions 14 as in the original construction, and operates in conjunction with the complementary parts 37, 37 37", 37 C as explained with reference to the parts 36 and 37 of the basic construction.

In addition to the modifications just explained, it will be manifest, without giving specific illustrations, that other constructional components may be variously altered in shape or arrangement without afiecting the practical results explained, or affecting the scope of my invention. It may, however, be convenient to briefly exemplify some, hence I will do so.

WVhat I claim and desire to secure by Let ters Patent is:

1. For drying road-making aggregates and other broken or'granular materials on the counter-current principle, apparatus comprising a casing; a plurality of open,- ended perforated notched short tubes or pipessituated within the casing in vertical and horizontal spaced relation to each other and to the casing; transverse imperforate plates fixed at intervals within the casing positioning the tubes or pipes, serving as a "means to control the direction of the circulapipes pass, means at the top of the casingfor receiving the material to be dried and delivering it to the tubes or pipes; means at the bottom of the casing for receiving-the material from the tubes or'pipes and discharging it; means establishing communication between one or more of the casing-compartments and asource of supply of a drying medium or agent; :and means establishing communication between the remaining compartment, or one ormore of the remaining compartments, and an outlet oroutlets for the-spent drying medium or agent and the :products of the drying operation.

2. F or drying road-making aggregates and other'brokenor granular materials on the counter-current principle, apparatus comprising tubes or pipes composed of a plurality of intercommunicating funnel-like members or tubes having staggered openings such as perforations or slots, in parts, and assembled'wvith their larger ends in juxtaposition-to the smaller ends of'the superjacent members or tubes'andmeans whereby the material passes sinuously in one'direction through :said tubes and "the drying agent passes in the other direction through said tubes.

3. For drying road-making aggregates and otherbroken or granular materials on the counter-current principle, apparatus comprising a casing; a plurality of short open-endednotched, funnel shaped or conical tubes or pipes situated Within the casing in vertical and horizontal spaced relation; means at the top ofthe casing for receiving the material to. be dried and delivering it to the tubes or pipes; means for supplying a drying medium or agentto the casing; means at the bottom of the casing for receiving the material unchecked-from the tubes or pipes and discharging it; and means for controlling the outlet including a revolubly-mounted disc; means for revolving said disc, said disc having one or more discharge openings therein.

4. For drying road-making aggregates and other-broken orgranular materials on the counter-current principle, apparatus comprising a casing; a plurality of notched open-ended short tubes or pipes situated Within the casing in vertical and'horizontal spaced relation, and communicating with the casing through openings provided in their Walls at intervals; means at the topof the casing receiving the material to be dried and delivering it to the tubes or pipes; means for supplying a drying medium or agentto the casing; means at the bottom of the casing receiving the materialfromthe tubes or pipes and delivering it to an outlet; and means inoludinga disc, having a'discharge'opening or 

